Crazy how much difference drag radials make, huh!

I have a Mark VIII. Runs a similar set up. Power dropped off at 5600. The Mach's cams are very similar, a bit more aggressive. By the looks of it, you spent a good amount of time in 2nd gear over 6k rpms. I would let first gear carry up to a hard redline shift, then shift 2nd and 3rd and around 6000. Second gear may be a bit off due to the tire spin, but thats what it appears with only a view of the tach and speedo.

if you look on dyno sheets Machs make peak power at around 6K anything after that your just wasting time.

Power fall's off around 6500,6600. Thats why I shift at around there.

take that bad boy to 6800 maybe even play at 7000